Central Nervous System Flashcards
Areas of the brain?
- Cerebral cortex
- Diencephalon
- Brainstem
- Cerebellum
Lobes of cerebral cortex?
Brodmann’s areas
Occipital, temporal, parietal, Postcentral gyrus, frontal lobe, precentral gyrus
Function of the occipital lobe?
Vision
Function of temporal lobe?
Auditory sensation, memory
Function of parietal lobe?
Somatosensation
Postcentral gyrus
primary somatosensory cortex
Responsible for proprioception
Function of frontal lobe?
Motor function
Function of precentral gyrus?
Primary motor cortex
Responsible for planned movements, language/speech
The diencephalon consists of:
Thalamus and hypothalamus
The brainstem consists of:
Midbrain, pons, medulla
Function of hippocampus and amygdala?
Long-term memory formation and emotional responses
Located in medial lobe
Function of basal nuclei?
Motivational/approach-related movement
The corpus striatum consists of:
Caudate, putamen, and globus pallidus
What is the caudate nucleus?
Long C-structure that follows cerebrum
The peripheral nervous system consists of:
Everything else other than brain and spinal cord
What is a ganglion?
Bundle of neuron cell bodies in peripheral nervous system
Used to describe some structures in CNS (ex. basal ganglia)
Cell types making up nervous tissue:
Glial cells and neurons
Function of glial cell?
Provide scaffolding and support structures for neurons and functions
True or False?
Glial cells can reproduce.
True
True or False?
Glial cells can produce nerve impulses.
False
Function of Neuron?
Communicates info within nervous system via nerve impulse conduction
True or False
Neurons are larger than glial cells.
True
True or False?
Neurons can have multiple processes from the soma.
True
True or False?
Neurons only have one axon emerging from the cell body and projecting nerve impulses to target cells.
True
Function of Myelin sheath?
Protects axon and promotes rapid transmission of info
Made from glial cells
Function of Node of Ranvier?
Allows ions to diffuse in/out of neuron for efficient propagation of nerve impulse
Formed from gaps in myelin sheath
Function of Dendrites?
Receive info from other neurons
Unipolar neuron consists of:
One process and includes both axon and dendrite
Receives sensory information
Location of bipolar neurons?
Mainly found in olfactory epithelium and retina
Multipolar neuron consists of:
Multiple processes, one axon and two or more dendrites
Gray matter consists of:
Cell bodies and dendrites
White matter consists of:
Myelin-insulated axons
Define:
Resting membrane potential
~60–70 mV, steady state of cell maintained via ion leakage and pumping
True or False?
There is more negative charge inside the neuron than outside the neuron.
True
How do neurons mantain negative internal charge?
- Selective membrane permeability
- Concentration gradient
- Electrostatic force
- Sodium-potassium pump
Define:
Depolarization
Cell becomes more positive and moves towards zero until threshold reached to get AP
Define:
Repolarization
K+ voltage-gated channels begin opening and returns membrane potential to -70 mV
Define:
Hyperpolarization
K+ voltage-gated channels remain open, delay in closing results in hyperpolarization
True or False?
Action potentials are all-or-none.
True
True or False?
Stronger stimuli equal larger action potentials (AP).
False
Stronger stimuli can initiate multiple APs more quickly though.
True or false?
All action potentials peak at the same voltage (+30 mV) and take place within ~2 ms.
True
Define:
Refractory period
Period of time where AP cannot be initiated due to other AP in progress
Process of action potential
- AP initiated at beginning of axon
- Signal propagates down axon due to Na+ channels opening
- Depolarization
- Signal terminates at axon terminal
Continuous conduction
Propagation along unmyelinated axon
Definition
Saltatory conduction
Propagation along myelinated axon
Definition
Graded potentials
Local changes in membrane potentials that vary in size
What are depolarizing graded potentials caused by?
Sodium or calcium ions entering the cell
What are hyperpolarizing graded potentials caused by?
Potassium leaving cell or chlorine entering cell
Definition
Postsynaptic potential
Graded potential in dendrites receiving synapses from other cells
Excitatory postsynaptic potential (EPSP)
Causes membrane potential to move towards threshold, more positive
Inhibitory postsynaptic potential (IPSP)
Causes membrane potential to move away from threshold, more negative
Ion channels are categorized by:
Charge or size of channel
Non-specific channel
Selective for charge but not necessarily for size
Ligand-gated channel
Neurotransmitter binds to extracellular portion of ion channel
Mechanically-gated channel
Opens because of physical change in cell membrane
Leakage channel
Randomly gated, helps particles cross cell membrane
Sensation
- Receives information about external environment
- Registers changes in homeostasis or in response to stimuli
Examples of sensory systems:
Vision, audition, somatosensory, olfaction, taste
Function of sensory systems?
Provides CNS with representation of external world and translates sensory information into a signal the brain can understand
Requires ascending mechanisms from receptor into CNS and descending mechanisms that sort through stimuli and influence ascending inputs
Define:
Integration
Typically occurs before response, sensory info from various receptors/structures transferred to nervous system for processing
Define:
Response
Produced by nervous system in response to stimuli as perceived by sensory structures
Perception
Conscious experience from stimulation of senses
Bottom-up processing
Occurs based on incoming data
Top-down processing
Based on knowledge
Sensory coding
Interpreting neural firing patterns as info about stimulus
Stimulus qualities encoded:
- Modality (light, sound, touch, etc.)
- Intensity
- Timing/duration
Common principles of all sensory systems:
- Receptors (specialized cells)
- Peripheral organization & processing
- Central pathways & processing
- Sensory cortices
Convergence
Information from many receptors sent to one ganglion neuron
Divergence
Each receptor sends information to multiple ganglion neurons
Labeled lines
Whenever particular population of neurons is active, specific stimulus is perceived consciously
Take-home
PNS organized into labeled lines dedicated to each sense
Blue DRG
Touch sensation
Red DRG
Pain sensation
Labeled lines receptors are selective in:
What activates them and to which cells they communicate